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19 Dec 2017, 22:49

(1) p is n% of n, this means p = n/100 * n = (n^2)/100 Here n is a positive integer, so n^2 is a perfect square. And n^2 must be divisible by 100, because then only p will be an integer. Now if we take square root both sides, we have √p = √(n^2)/ √100 = n/10Since n^2 is divisible by 100, this means n must be divisible by 10. So √p is an integer. Sufficient.

(2) p is divisible by 100. If p = 400, then √p = 20 is an integer. If p = 300, then √p = 10 √3, is not an integer. So Insufficient.

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19 Dec 2017, 23:34

If p is a positive integer is √p a positive integer?

(1) p is n percentage of n where n is a positive integer --> p = n/100*n = (n/10)^2. Now, n is an integer, so n/10 is either an integer or a fraction but since p is an integer and fraction^2 cannot be an integer, then n/10 can only be an integer, thus p = (n/10)^2 = integer^2. Sufficient.

(2) p/100 is a positive integer. If p = 100, then the answer is YES but if p = 200, then the answer is NO. Not sufficient.